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A technical look at Iran's internet shutdowns

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Re: A technical look at Iran's internet shutdowns

#61

Post by CaptainFever »

bawolff wrote: post #32

> IPv4 addresses are limited and constantly reallocated. Most are rented and passed between hosting providers, resold between datacenters, or migrated across regions. The Iranian filtering system uses GeoIP databases and BGP information to decide which IP ranges to trust and which to block. But those records lag behind the changes. This is surprising to me. Surely iranian ISPs would have directly allocated IP space?…

I'm ignorant about this, but I'm surprised there isn't just some physical switch that just straight up airgaps all network routes going out of the country.

Re: A technical look at Iran's internet shutdowns

#63

Post by znano »

one-note wrote: post #23
RiverCrochet wrote: post #3

I wish this article went into more details on what the "National Information Network" is. I would guess it's at least a set of nationally managed DNS servers that will always resolve national IPs even if upstream global DNS is cut off. Looking at a bigger picture though, honestly I think we're seeing the end of the raw global Internet for the masses. 20 years ago, it seemed impossible, but here we are. It's simply no…

The only way to have global uncensored sharing of information is shortwave radio. Always has been, always will be.

Yeah, also a good source of getting information from the world in full internet shutdowns.

Re: A technical look at Iran's internet shutdowns

#64

Post by znano »

elternal_love wrote: post #34

If you are ever thinking of writing somethings like this: please be aware that people could be executed based upon the validity of your assumptions and advice offered.

for what? nobody should follow anything blindly and im sure people in iran are more aware of this and they know how to take security precautions.

Re: A technical look at Iran's internet shutdowns

#67

Post by MangoToupe »

bawolff wrote: post #52
heraldgeezer wrote: post #45

Earlier quoted context omitted.

Even tech people? wowe

You mean that group that still calls TLS SSL even though its been 26 years?

The important part is its use. You could call it magic key negotiation and I wouldn't care. RCS and SMS are fundamentally different technologies in every way.

Re: A technical look at Iran's internet shutdowns

#69

Post by mschuster91 »

kortilla wrote: post #40
mschuster91 wrote: post #16

Earlier quoted context omitted.

> hams have their own packet radio stuff We got basically three different things. First we got APRS, mostly used for position reports (go on aprs.fi for a map). That is pretty nice but unusable for anything more than a SMS worth of things, and you need repeaters and not just internet gateway collectors to actually have something that's resilient. Next thing is AX25, the technical foundation behind APRS. Yes you can u…

> but it's about modem speeds so virtually useless outside of toying around. I don’t understand this sentiment. For exchanging information, modem speeds were great. Wikipedia, forums like this one, instant messengers, etc all worked fine

> Wikipedia, forums like this one, instant messengers, etc all worked fine

The problem is, websites got wasteful. You're not going to get any modern website - including Wikipedia - to load in anything close to usable waiting times over a modem speed constraints. HN and maybe Old Reddit are an exception but HN is a niche forum and Old Reddit is probably going to get dumped once Reddit manages to port over all features that were only exclusive to Old Reddit for like six years or so. IRC is all but gone, in no small part "thanks" to Freenode going down the drain and Slack/Discord/Teams eating its lunch.

Re: A technical look at Iran's internet shutdowns

#70

Post by mschuster91 »

swores wrote: post #20
mschuster91 wrote: post #16

Earlier quoted context omitted.

> hams have their own packet radio stuff We got basically three different things. First we got APRS, mostly used for position reports (go on aprs.fi for a map). That is pretty nice but unusable for anything more than a SMS worth of things, and you need repeaters and not just internet gateway collectors to actually have something that's resilient. Next thing is AX25, the technical foundation behind APRS. Yes you can u…

Am I right to assume that it's easy to locate the source of ham radio signals? i.e. if there's a blanket ban, can you use your radio hidden in your house or can the government easily find out that the user they've noticed on the airwaves is located there and knock down your door?

> can the government easily find out that the user they've noticed on the airwaves is located there and knock down your door?

Sadly, yes. A bunch of SDRs spread over the whole country with precise clocks or a scheme like the one used in ADS-B MLAT reception (that's based on using the internal SDR clocks without requiring precise clocks on the host) is enough to use multilateration to hone in on any kind of signal, even looking up in raw signals in the past.

If I were to guess, I'd assume that even in nominal democracies the secret agencies are already running such monitoring stations so it's probably already the case that, should need be, all communications can be triangulated.

The HF bands are all small enough to be sampled whole with a single cheap RTL-SDR each, a KiwiSDR can sample literally all of them at the same time, only the VHF/UHF bands need more dedicated equipment (e.g. a BladeRF) - all of that is inside the range that hobbyists can easily afford.

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